[A proposal of a T.N.M. type of classification of the ear. O.P.A.C. classification of chronic surgical otitis]

With the advent of modern otology, cophosurgeons anxious to compare their results soon became aware of the need for a "T.N.M" type of classification for the ear. The classification described here by the authors is, in principle, a classification of the "T.N.M" type: that is, a purely descriptive classification without prognostic, pathogenetic or therapeutic pretensions. This "O.P.A.C." classification is based on a description of 4 main characteristics: 1) the existence and characteristics of potential otorrhoea, described under the letter C; 2) the characteristics of potential perforation of the tympanum, described under the letter P; 3) the appearance of the middle ear, excluding the ossicular chain, described under the letter A; 4) the condition of the ossicular chain when the surgeon has completed his exploration of the lesions, described under the letter C. Two years experience seems to have proved the convenience and usefulness of this purely clinical classification, providing otologists with a common language. While they are aware of the objections and criticisms to which it may give rise, the authors hope, on time, to improve in this classification.